PREGNANT SMOKERS' DEADLY LEGACY

Scientists find clear evidence that women using tobacco pass on a strong
'cancer trigger' to unborn children John von Radowitz

CLEAR evidence that pregnant women who smoke transmit a powerful cancer
trigger to their babies has been discovered for the first time by scientists.

One of Britain's leading cancer experts described the findings as "absolute
dynamite".

Researchers in the United States found by-products of a nicotine-derived
chemical called NNK in the urine of infants born to smoking mothers. NNK,
unique to tobacco. is one of the strongest carcinogens in tobacco smoke.

The results from the University of Minnesota Cancer Center in Minneapolis,
suggest that alarming amounts of the chemical pass through the placenta to
be broken down in the unborn baby's body. Levels of the NNK by-products in
the babies were about 10 per cent of those found in the urine of adult
smokers - two and a half times the adult concentration, weight-for-weight.

Women are strongly advised not to smoke during pregnancy but until now all
the evidence of harm to the foetus has been based on statistical
correlations. Babies whose mothers smoked when pregnant were more likely to
be small, under-weight, have low intelligence and suffer from glue ear.

There is also some suspicion that leukaemia rates are higher in children
whose mothers smoked during pregnancy.

The new findings, presented at the annual meeting of the American Chemical
Society in Boston, are the first to show that a cancer-causing substance
specific to tobacco is transmitted to the foetus.

Professor Gordon McVie, director general of the Cancer Research Campaign.
said: "This is absolute dynamite. It's awful. Here we have cast-iron,
water-tight evidence that the baby is exposed to carcinogens thanks to the
mother's smoking habits."

A team of scientists led by Dr Stephen Hecht tested samples of the first
urine passed by 48 babies, from both smokers and non-smoking mothers, sent
to them by collaborating researchers in Germany.

In 22 of 31 samples from new-born babies whose mothers smoked during
pregnancy they found NNK metabolites - chemicals left after a substance is
broken down by the body.

No metabolites of the carcinogen were found in samples from babies whose
mothers did not smoke.

Dr Hecht called the findings "an unacceptable risk". He said the levels of
NNK by-products found were "substantial when one considers that exposure of
the developing foetus to NNK would have taken place throughout pregnancy".

Prof McVie said he was surprised and alarmed by the high levels of
metabolites discovered. "The average baby weighs about three kilos, so
you're looking at a concentration in the urine something like two and a
half times that of an adult, weight for weight," he said. "The chemical has
gone through the whole body. It's passed through the blood system, been
metabolised, gone through the liver and reached the kidneys. All the
tissues in the body must have seen it."

The research was an extension of previous work from Dr Hecht which last
year showed that NNK is found in non-smoking adults who breath in other
people's smoke at work

Dr Hecht pointed out that since most women who smoke during pregnancy
continue the habit afterwards, their children are exposed to the dangerous
chemical for many years.

Clive Bates, director of Action on Smoking and Health, said: "Babies
exposed to cancer-causing chemicals in the womb are suffering from one of
the nastiest forms of passive smoking."

Checked-by: Mike Gogulski